Mechanical stoker



Dec. 12, I939. M. E YEAGER MECHANICAL STOKER Filed Feb. 11, 1939 4 Sheets-Sheet 1 MAMAA Afforyzey Dec. 12, 1939. M. E. YEAGER MECHANICAL STOKER 4 Sheets-Sheet 2 Filed Feb. 11, 1939 a I W M. E. YEAGER MECHANICAL STOKER Dec. 12, 1939.

Filed Feb. 11, 1939 4 Sheets-Sheet 3 Dec. 12, 1939. Y M EYEAGER 2,183,386 I MECHANICAL STOKER Filed Feb. 11, 1939 4 Sheets-Sheet 4 mam M A ffrvz ey Patented Dec. 12, 1939 at or ies MECHANICAL STOKER Milburn E. Yeager, Needham, Mass., assignor to National Engineering & Mfg. 00., Inc., a corporation of Rhode Island Application February 11, 1939, Serial No. 255,851

6 Claims. (o1. 110'36) Fig. 11 is a perspective View of the guide My present invention relates to a stoking apparatus, and more particularly to a combination stoker and rotating grate.

The principal object of the present invention is to provide an apparatus for simply and efficiently feeding measured quantities of coal to a revolving grate of a furnace.

Another object of my invention is to provide a combination stoker and grate which will dis.- tribute the fuel uniformly in the most economical manner for consumption on the grate and eliminate waste. p I

Another object of the present invention is to provide a stoking apparatus and grate which will eliminate'the accumulation of ash tending to clogthe circulation of air and the fire draft.

Another object of the present invention is to provide a combination stoker and grate having a novel type of draft distribution which will insure an even and economical burning of the fuel at all points on the grate.

A further object of the present invention is to provide an apparatus having the above advantages which is easy and economical to manufac: ture and assemble and which is composed of a plurality of readily replaceable parts.

With the above and other objects and other advantageous features in view, my invention consists of a novel arrangement of parts more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claims appended hereto.

In the drawings:

Fig. 1 is a top 'plan view, partly in section, of my newcombination stoker and grate;

Fig. 2 is a section taken along line 2-2 on Fi Fig. 3 is a plan view of the grate, partly in section, showing the rotating mechanism;

Fig. 4 is a section taken along line 4-4 on Fig. 1; p

Fig. 5 is a detailed sectional view of the feeding and rotating apparatus;

Fig. 6 is a section taken along line iion Fig.

. Fig. 7 t is a section taken along line 'l? on.

member.

Referring more in detail to the drawings illustrating my invention, the numeral generally designates a conventional steam boiler, or the like, having a lower annular base portion 2i adapted to hold the grate, firebox, and ash pit, and an upper portion 22 housing the Water jacket 23. Below the level of the lower portion 2| is a wind boX or air chamber. In the center of wind box 24 is an ash box 25comprisinga three-sided, metallic, rectangular box having a cover 26. The front open side of the box 25 is provided with an inclined passageway portion 27 leading to the bottom of the front of the furnace and closed by a door 28.

Referring to Fig. 4, the cover 26 of the box 25 comprises an annular plate having a central opening 29 and surmounted by an annular ridge or flange portion 39. The ridge or flange is centrally grooved as at 3i to form a bearing surface for receiving a plurality of conventional ball bearings 32. The cover 26 is also provided, in the opening 29, with four integral laterally extending tongues 33 equally spaced about the inner periphery of the opening 2s.

Rotatably mounted on the bearings 32 in the groove 3! is a turn table 34 having an outer annular flange 35 with a depending portion surrounding the upturned flange 3i Theflange 35 is provided with a bearing groove 36 adapted to ride over the top of the bearings 32. The turn table 3i comprises two vertically spaced inwardly extending flanges 3'! and 38. The flange 3? extends to the inner edge of the opening 29 in the cover 26 and the flange 38 extends inwardly a lesser distance. A table plate 39 is keyed to the turn table 34 and is rotatable therewith. The table plate 39 is made up of a plurality of sections 40, see Fig. 3, having tapered side edges and forming a central opening 4! above the central opening in the turn table and cover 25. Integrally formed with each section lli of the plate 39 are vertically disposed ratchet teeth 42. The inner edge of each section 4!] is provided with a. slot 43, each slot 43 registering with a slot M in the flange 38. The sections All are bolted together on the table plate 39 on each side of the slots 43, as shown in Fig. 3.

Radially disposed about the upper surface of the plate 39am a plurality of interlocking grate portions 15 disposed as in Figs. 1 and 3. Each grate portion 45 comprises an upper flat portion 46 provided with a plurality of air openings 4?, and two spaced feet or flanges 48 (see Fig. 2),

providing an air space or passageway 49 beneath the upper portion 46. Referring to Fig. 2, each section 45 is provided with an integral laterally extending flange 58 on a side edge below the top and an integrally laterally extending flange 5| on opposite side at the top so that when each complementary section 45 is placed next to a similar section the upper flange to the right will ride upon the loWer flange to the left of the next section, thus interlocking the various sections. Each of the segments 45 is bolted at its outer edge, to the table plate sections 48, as by means of bolts 52.

Extending around the upper outer surface of the grate portions 45 is a seal ring 53 made in a plurality of sections, each section having an extended prong 54 on one side adapted to slide into a cut-out portion 55 in the adjacent flange portion. The inner edge of the plate 39, surrounding the central opening M, is surmounted by an annular L-shaped casting 56 also made in a plurality of sections, each section provided at its inner edge with horizontally spaced slotted openings 5? providing air passageways. The underside of each of the segments 56 is provided with an integral depending lock tongue 58 extending through the slotted openings 43 and 44 and locking the plate sections 48 to the plate 39 and to the turn table 34.

The inner edge of the lower portion 2| of the boiler 28 is provided with a plurality of angle irons 59 adapted to support a laterally extending annular plate 88 made in sections 6!, suchas those shown in Fig. 8. Each plate 6| is provided with a central depending flange 62 and an inner depending flange 83 having spaced expansion slots 64. The flanges 62 and 63 are adapted to be positioned on the inner and outer peripheries respectively of the seal ring 59 as shown in Fig. 4. Referring to Fig. 8, the upper edge of each of the sections 6| is provided with a plurality of evenly spaced angularly cut-out platforms 55. Mounted on the flange 6| is an inner flange 86, shown in Fig. 9, comprising an inner flange portion 61 having a plurality of spaced expansion slots 68, and having laterally extending angularly cut-out tongues 69 adapted to interlock with the platforms 65 on the portion 6|. An L-shaped fine brick may be used instead of the flange 66.

Near the front of the furnace, the top of the stationary flange 6| is clear of the cut-out portions 65 and is overlapped by the inner edge of a plate I8 which curves inwardly to form an apex 'II extending towards the center of the grate. The plate I8 is slotted, as at I2, and is provided with integral lock pins I3 on the under surface thereof. Mounted beneath the plate I8 is a flange I4, shown in Fig. 11, which has a depending wall along the inner edge of the grate and extending towards the center thereof. The depending wall I5 is slotted, as at I6, and has an upper integral plate portion 'II adapted to extend beneath the plate I8. The upper plate portion I7 is provided with an opening 18 to which it can be pinned to the plate I8 and interlocking slots I9 adapted to interlock with the pins I3 to permit a floating action.

The opening in the central portion of the grate is provided with a drop cover 88 which is pivoted, as at 8|, to a frame 82, set in the inner periphery of the opening. The frame 82 comprises two segments having depending flanges 83 resting on the tongues 33 in the lower cover 26. The two segments are bolted together in the front and rear portions as at 84. Referring to Fig. 4, a rod 85 is pivoted to the underside of the cover 88 and extends through a slot 86 to the front of the furnace. The protruding end of the rod 85 may be provided with a suitable handle 81 and an intermediate portion thereof, adjacent the slot 86, may be provided with a shoulder 88. When the rod 85 is pulled outwardly by means of the handle 81, it will swing the cover 88 upwardly to close the opening, the shoulder 88 engaging the lower end of the slot 85 to hold it in place.

The above description completes the structure of the grate portion of the furnace of the present invention. As can readily be seen, the ash pit box 25, its cover 26, the frame 82, and cover 88 in the central portion are stationary. The turn table 34, gears 42, plate 39, the segments 48, the grate members 45 and the seal rings 53, including the portion 56 surrounding the central opening, are all rotatable. The angle irons 59 supporting the plate 68 and angle irons 6|, 66, and members I8 and I4 are also stationary. The internal firebrick 89 is built upon the plate 68 and supported by the angle iron 59, as shown in Fig. 2.

The stoker mechanism comprises a hopper 98 communicating with a horizontal channel 9| which extends through the firebrick 89 through an opening 92 as shown in Figs. 1 and 2. Referring to Figs. 5 and 6, a ram 93 is slidable within the channel 9|. The ram is actuated by a connecting link 94 which is in turn operated by means of the slidable sleeve 95, operated by a crank and motor movement not shown. The stroke of the link 94 may be regulated by means of the adjustable abutment collar 91 in the rear portion thereof; a stationary collar 98 is provided as an abutment for the sleeve 95. Depending from the ram 93 is an arm I88 to which is attached a horizontal bar I8I having a vertical plate I82. Extending from the lower end of the plate I82 are a pair of parallel bars I83 held in rigid position by means of angle irons I84. The bars I 83, see Fig. 5, are journalled in a pair of bearings I 85 for horizontal reciprocation. A plate I86 straddles the bars I83 between the bearings I85 and carries a pawl I81 which is adapted to engage the teeth 42 on the turn table. The pawl I8I may be spring pressed, as shown, or may be actuated by a counterweight. The slant of the teeth and the disposition of the pawl is such that forward movement of the pawl causes rotation of the turn table and grate in a clockwise direction.

The motor used to operate the ram heretofore described may also be used to operate the conventional blower I88 which communicates through the passageway I89 with the lower portion of the surface surrounding the outside of the ash box 25, as shown in Fig.7.

The operation of the apparatus can now be described as follows: The hopper 98 is filled with coal. When the ram 93 is drawn back in a position shown in Fig. 6, the coal will enter the passageway 9| and the forward movement of the ram 93 will push the coal upon the grate 45 adjacent the outer periphery thereof corresponding to the outer edge of the grate shown in Fig. 1. At the same time the rod I8I will push the plate I82 and the rods I83 so that the pawl I81 will engage the ratchet teeth 42 and turn the turn table, and the grate portions in a clockwise direction. The ram now moves back, and the ram will again turn the turntable and deposit another portion of coal behind the first portion deposited. As the ram continues to operate and the turn table continues to turn, the coal, ignited by the burning fuel previously placed in the furnace,

. center by the portions 10 and 14, the previous portions are pushed further and further along towards the center of the grate, the timing being such that when the coal is approximately completely consumed and turned to ash, it will be pushed from the rotating inner portion 51 onto the closed door 80. Thus, the grate will be always entirely free of ash and will hold only burning fuel. When a sufficient quantity of ashes have accumulated on the drop door 80, it is mere- 0 ly necessary to lift the handle 81 and bar 85 and move it forwardly. This will swing the door 80 downwardly and allow the ashes to drop into the box 25 from whence they can be removed through the door 28. The door can then be swung back into closedposition by hooking the shoulder 88 over the edge of the slot 86.

While this is going on, the grate is furnished with a proper draft from the blower I08 through the passageway Hi9 and into the wind box, but

0 not into the ash box, so that the draft is confined to the outside ofthe ash box as shown in Fig. '7. As can readily be seen in Fig. 2, the draft flows upwardly and enters the passageway 49 beneath the grate portions 45, up through the openings 41 and through the various slots dis-- posed about the inner periphery of the grate to form an upward current of air to burn the fuel entering from the outer side edge. This current of air is so disposed that it will not disturb or swirl any of the ashes nor can it be clogged by any ashes or accumulated waste material.

If desired, the inwardly extending plates 10 and M may be surmounted by an additional plate I I0 pivoted at HI and connected to the plate I02 .5 which operates the ram, by a rod H2. With this connection, the portion H0 will be swung forwardly with each deposit of fresh coal upon the grate to give the partially burned coal an additional push towards the center of the grate.

10 While the drawings and description show a ram stoker and ratchet and pawl drive, it is possible to use a screw in the passageway 9| for continuously pushing a quantity of coal upon the grate. Instead of the pawl and ratchet arrange- ;5 ment a worm drive may also be used on the grate semble and are admirably adapted for the in-.

tended purpose. In view of the intense heat at the point of fuel consumption in similar types of 0 grates, it is often very difficult to replace burntout and cracked parts. By utilizing the construction of the present invention, it is very simple to replace particular broken sections without disturbing. the entire arrangement. Further- 5 more, the parts are so interlocked that thereiis little' or no seepage of air causing cross drafts where'itis not wanted or required. By utilizing the construction of the present invention, the

ash pit is free of any draft and the draft is directed to the proper place directly beneath the burning fuel by means of special channels beneath each particular grate segment.

While I have described a specific constructional embodiment of my invention, it is obvious that any change in size and shape of the various parts and in their arrangement may be made to suit the requirement for different installations without departingfrom the spirit and the scope of the present invention, as defined in the appended claims.

I claim:

1. In a mechanical stoker, an annular rotatable grate, said grate comprising a plurality of sections having draft flow passageways extending laterally beneath the upper surface of said grate and communicating therewith, a fuel hopper, means for positively feeding measured quantities of fuel from said hopper tangentially tothe outer edge of said grate, and for rotating said grate in timed relation to the positive feed of the fuel, and means positioned at the outer edge of the grate and adjustably movable inwardly for guiding the burning fuel in concentric circles on said grate progressively toward the center of said grate.

2. In a mechanical stoker, an annular rotatable grate, a fuel hopper,an ash box beneath said grate communicating with the central portion of said grate, means for positively feeding measured quantities of fuel from said hopper tangentially to the outer edge of said grate, and for rotating said grate in timed relation to the positive feed of the fuel and means positioned at the outer edge'of the grate and adjustably movable inwardly for guiding the burning fuel in concentric circies on said grate progressively toward the center of said grate. I

3. In a mechanical stoker, an annular rotatable grate, a fuel hopper, means for positively feeding measured quantities of fuel from said hopper tangentially to the outer edge of said grate, and for rotating said grate in timed relation to the positive feed of the fuel, and means positioned at the outer edge of the grate and adjustably movable inwardly, for guiding the burning fuel inconcentric circles on said grate progressively toward the center of said grate, said feeding means including a motor-driven rain reciprocatable in a passageway between said hopper and the upper surface of said grate.

4. In a mechanical stoker, an annular rotatable grate, said grate comprising a plurality of sections having draft flow passageways extending laterally beneath the upper surface of said grate and communicating therewith, a fuel hopper, means for positively feeding measured quantities of fuel from said hopper tangentially to the outer edge of said grate, and for'rotating said grate in timed relation to the positive feed of the fuel, means positioned at the outer edge of the grate and adjustably movable inwardly for guiding the burning fuel in concentric circles on said grate prcgressiveiy toward the center of said grate, and

a blower for forcing a draft through said draft flow passageways.

5. In a mechanical stoker, an annular rotatable grate, a fuel hopper, an ash box beneath said grate communicating with the central portion of said grate, means for positively feeding measured quantities of fuel from said hopper tangentially to the outer edge of said grate, and for rotating said grate in timed relation to the positive feed of the fuel, means positioned at the outer edge of the grate and adjustably movable inwardly for guiding the burning fuel in concentric circles progressively toward the center of said grate, and a blower for forcing a draft beneath the burning fuel on said grate.

6. In a mechanical stoker, an annular rotatable grate, said grate comprising a plurality of sections having draft flow passageways extending laterally beneath the upper surface of said grate and communicating therewith, a fuel hopper, means for positively feeding measured quantities of fuel from said hopper tangentially to the outer edge of said grate, and for rotating said grate in timed relation to the positive feed of the fuel, and means positioned at the outer edge of the grate and adjustably movable inwardly for guiding the burning fuel in concentric circles on said grate progressively toward the center of said grate.

MILBURN E. YEAGER. 

